- Why should I use Allele Diagnostics?
- At Allele Diagnostics, our main focus is providing quality results quickly. We are cognizant that many patients are dealing with life-critical questions. We value a comprehensive approach to testing that takes into consideration not just the laboratory test, but also client support - through reporting and our genetic counseling services - to help the physician navigate the intricacies of the result.
- How do I order a test?
- Test requisitions may be printed from our website and sent with the sample. Additionally, our online ordering system will be available so that you may log on to our secure customer service web portal to order your testing online. This portal will allow you to receive your patient's report, as well.
- What are your sample requirements?
- Microarray testing can be performed on a variety of specimen types. For neonatal/pediatric cases, we can accept peripheral blood, buccal swabs, and previously extracted DNA (See our DNA acceptance policy -footnote 2 on the sample requirements page). For prenatal cases, rapid microarray is available on direct amniotic fluid samples and all cultured cells. Please call to inquire about availability for direct CVS or POC specimens.
- Karyotype and FISH analysis currently can be performed on peripheral blood. Prenatal karyotype is available through our partner lab.
- FISH analysis may also be performed on a fixed cytogenetic pellet or a submitted cytogenetic slide.
- Sequencing panels and single gene analyses can be performed on peripheral blood.
- Do you require maternal cell contamination studies for microarray testing?
- Maternal cell contamination (MCC) studies are strongly recommended for our prenatal microarray tests (test #110 and test #111). This test is used to rule out the presence of maternal cell contamination within a fetal sample, as the potential presence of maternal cells within a prenatal sample can lead to an inaccurate interpretation of DNA based test results. Please submit 3-5 mL maternal blood in EDTA or a buccal swab for this test.
- What are your minimum specimen requirements for newborns?
- For microarray or microarray and karyotype, we require at least 0.5 mL of blood in a NaHep vacutainer or microtainer for newborns. This specimen is also adequate if follow-up FISH is required. An EDTA specimen is ideal for any additional molecular testing, so if additional testing is indicated, please call us at 844-ALLELE2 (255-3532) to discuss.
- What are your minimum specimen requirements for prenatal specimens?
- For microarray and karyotype, we require at least 25 mL whole amniotic fluid, 15 mg chorionic villi in sterile media or saline, 15 mg products of conception in sterile media or saline, or 1 T-25 flask that is 70% confluent. We also accept DNA for microarray testing and require a minimum of 2 μg.
- Is there a difference between submitting a buccal swab and a peripheral blood sample?
- Microarray testing can be performed from either sample. However, both karyotype analysis and FISH testing is only possible if submitting a peripheral blood specimen received in sodium heparin (green top). If microarray is performed from a buccal swab and results are abnormal, we may recommend a secondary (blood) specimen for visualization of the abnormality.
- Does Allele Diagnostics require consent forms?
- Consent form requirements vary based on the state from which the sample is submitted. We recommend that all genetic tests are ordered following a thorough discussion between the provider and patient in which the pros and cons of the testing are discussed, however we do not require that we receive a copy of the consent form to process a sample.
- If additional testing is needed for my patient do I need to submit a new sample?
- Stabilized DNA specimens are held unless prohibited by specific state mandates. Please contact our laboratory to assess if sufficient sample is available. Specimen availability is dependent upon when previous testing was performed, the type of testing that was performed, and the type of testing that will be ordered. Note that karyotype and FISH analysis is not possible on archived DNA samples.
- What about parental testing?
- As with most genetic tests, the results obtained from our microarray and karyotype services affect not just the patient but the family as a whole. Parental testing may be recommended for identification of carrier status and for determination of recurrence risk, and in these instances the testing is clinically indicated. For findings of unclear clinical significance, parental testing could be considered, but may not be informative since many genetic disorders manifest in complex and variable phenotypes and finding a similar copy change in a parent does not necessarily exclude a causal relationship. Parental testing should be considered on a case-by-case basis. There is generally a charge associated with parental testing. If you have specific questions, we recommend calling us at 844-ALLELE2 (255-3532) or emailing at firstname.lastname@example.org.
- Do you accept samples on Saturdays?
- Yes. If sending a sample on a Friday, please be sure to mark the FedEx airbill appropriately noting Saturday delivery.
- After testing is completed, can I request that DNA be shipped from Allele Diagnostics to another laboratory?
- Yes. If you have additional testing to perform, we can share the sample with one of our partner laboratories to complete your testing needs. If you have a specific laboratory in mind or are requesting that DNA be returned to you or shared with a DNA bank, we can forward DNA per your request. We ask that you fill out a specimen release form and provide shipping arrangements, such as a FedEx account number if the specimen will be sent somewhere other than one of our partner laboratories. Note that as specific sample requirements for additional testing may vary, it is possible that an additional sample beyond the DNA that we have available may be required by the laboratory receiving the specimen.
- What is the 5-cell karyotype + array bundle, and why would I want to order it?
- A microarray analysis provides information about DNA copy number changes and is better able to identify both microscopic and submicroscopic deletions and duplications associated with genetic disorders than traditional karyotype. However, microarray cannot identify balanced rearrangements, Robertsonian translocations, and some instances of triploidy. A combination of limited karyotype and microarray will identify both microscopic and submicroscopic unbalanced alterations and microscopic balanced alterations.
- In the prenatal setting, what is the difference between the high resolution rapid microarray (test #110) and the targeted rapid microarray with backbone (test #111)? When would I order each?
Both tests have the ability to identify more than 255 genetic syndromes and are useful for rapidly detecting most large and small structural chromosome abnormalities as well as copy neutral absence of heterozygosity. FISH visualization of aberrations is included in both tests.
Our high resolution rapid microarray is able to detect abnormalities larger than 20 kb in targeted regions of known syndromes, whereas the targeted microarray with backbone detects abnormalities larger than 40 kb in targeted regions of known syndromes. The tests also differ in the density of their backbone coverage. This means that the high resolution microarray can detect abnormalities 80 kb or larger in the backbone region, whereas the targeted array will only detect abnormalities greater than 400 kb in the backbone region, potentially lessening the chances of an unclear result. Please contact our Genetic Counselors for assistance in determining the best test option for your patient.
- I need a rapid result on a neonate. Can I order aneuploidy FISH?
- Rather than performing aneuploidy FISH, our rapid array can provide information about all abnormalities that aneuploidy FISH targets, and results are typically reported within two business days of specimen receipt. The added benefit of the array is the superior resolution as compared with aneuploidy FISH. In addition to detection of trisomies, the array can identify microdeletions and microduplications that may present with severe features, such as multiple anomalies, and identification of these abnormalities can provide you with quick answers to help guide management decisions for babies in the NICU.
- My patient had a karyotype and Fragile X testing already. Why should I order an array instead of exome sequencing?
- ACMG guidelines indicate that microarray testing for patients with developmental delay, dysmorphic features or intellectual disability should be a first line test (Manning & Hudgins, 2010). A microarray provides a rapid, whole genome evaluation at a high level and can exclude copy changes either outside of the coding sequences or in regions that perform poorly with sequencing that may still affect gene expression. In addition, recent studies have shown that microarray test results can directly and immediately impact patient care (Miller et al. 2010, Ellison et al. 2012, Henderson et al. 2014).
- Is your microarray FDA approved?
- No. The array in use at Allele Diagnostics is a custom-designed microarray which has been extensively validated for use as a laboratory developed test following ACMG and CAP standards. The microarray is designed with coverage over clinically relevant regions and genes known to be involved in genetic diseases. Our internal validations have ensured the validity of the testing performed.
- What information do SNPs provide?
The SNP component of this microarray will detect long continuous stretches of homozygosity (or absence of heterozygosity, AOH). AOH can be indicative of uniparental disomy (UPD) if within a chromosome, or an increased risk of a recessive disorder if identified across multiple chromosomes. Note that for some regions of the genome, AOH of 8-10 Mb may be within normal limits and will not be reported.
There are a small number of chromosome regions which are associated with imprinting or UPD disorders. AOH of 5 Mb or more will be reported for the following regions:
- Chromosome 6: paternal UPD and transient neonatal diabetes (specifically 6q22-q24)
- Chromosome 7: maternal UPD and Russell Silver syndrome
- Chromosome 11: Beckwith Wiedemann syndrome (specifically 11p15)
- Chromosome 14: maternal UPD and Temple Syndrome, or paternal UPD
- Chromosome 15: Prader Willi syndrome or Angleman syndrome
The SNP component of this assay also has the ability to determine an overall level of homozygosity throughout the genome of 5% or more. If identified, this will be reported as it may be reflective of identity by descent and an increased risk for recessive disorders. Specific details about the family history may only be available to the ordering clinician. Thus, clinical correlation and correlation with family history is required to properly assess a potential for relatedness.
Note that the failure to detect AOH does not exclude the clinical diagnosis of an imprinting or recessive disorder. In addition this assay cannot determine whether the alteration is paternal, maternal or de novo in origin. Additional UPD or molecular testing may be required.
- What if I have questions about the test results?
- Our genetic counselors are available to discuss the test results and can assist you in coordinating any additional testing your patient may need. Our goal is to provide a clear and comprehensive report that is understandable. However, we recognize that questions may arise about any patient's result, so our genetic counselors are available to discuss your questions or concerns.